Liquid-fuel burner



R. G. MARX.

LIQUID FUEL BURNER.

APPLICATION `FILED APR-11.1917- 1,3'78,480. Patented May 17, 1921.

WITNESS '1N VEA/TOR.

fgfmw l// A TTORNE YS ROLAND GvMARX, 0F PALO ALTO, CALIFORNIA.

traum-runt; BURNER..

y terasse.

Specification of Letters Patent.`

Patented May l?, i921 application med April 11, i917. Serial No. 161,173.-

vehicles, domestic water or air heaters and other devices.

An object of the invention is to provide a burner which will produce a combustible mixture when cold and which varies the .mixture as the temperature of the burner increases. v

Another object of the invention is to provide a. 'liquid fuel burner which will produce perfect combustion of the fuel.

Another object of the invention is to provide a burner which is so constructed that a large volume-of explosive mixture is not present at any time, thereby eliminating the possibilities of dangerous back-fires.

A further object of the invention is to provide a burner which is quiet in operation.

rlhe invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description, 'where l shall outline in full that form of the invention which l have sel'ted for illustration in the drawings accompanying and forming part of the present specification. In said drawings l have shown one specific form of my generic invention,y but it is' to be understood that 'l vat do not limit myself to such form, because the invention as expressed in the claims may be embodied in a plurality of forms.

Referring to said drawings:

Figure lis a vertical section of a burner embodying my invention. Y

Fig. Z is across section of a portion of the burner on a larger scale.

Fig. 3 is a cross section of a portion of a modified form of burner.

rlhe burner of my invention contains features which particularly adapt it for use in connection with the boilerspf steam-driven automobiles, domestic water'and air heaters and devices wherein gas is at present used as fuel. lt produces a hot, clean llame in which the mixture of air and fuel is such stares rarest orales.

that the :dame will not attack the material of the boiler or other device in which it is used. The burner is constructed so that a combustible mixture is produced very quickly after the feed of fuel is started, so that a large amount of explosive mixture' of air and fuel is not present, thereby'eliminating back-fires and so that the flame does not vibrate, thereby eliminating the whistling noise so common in prior burners.

ln the present construction, air is blown through a passage into which the liquid fuel is introduced, and the fuel is broken up and picked up by the air, producing a combustible mixture. Other conditions being equal,

the rate at which the air will break up and pick up the fuel, depends upon the vel have so constructed. the burner that, when cold, the air in contact with the fuel moves at a higher velocity than when the burner is heated.v The heat greatly assists in vaporizing the fuel and consequently it is not necessary to move the air at such high velocity when the burner is heated, and the present burner accommodates itself to this situa-l tion automatically and causes the velocity of the air to decrease' as the temperature of the burner increases.'

The burner comprises an air'c'hamber Q, which may be of any desired shape, that shown in the drawing being annular, into which air is forced by a suitable blower 3 tially, so that the airis distributed equally to all parts thereof. At its lower inner Eportion the air chamber is provided with a trough or cup 5, the outer wall 6 of which is preferably inclined from the vertical, so that the width of the trough@ gradually de# creases downwardly. Fuel, from a suitable pump or measuring device 7, is fed yinto the trough through the pipe 8,y which extends through the outer wall 6.

Engaging the upper wall of the air chamber S2 and. extending down into the trough 5 is a blade 9, which, with the outer wall 6 of the trough, forms a passage of ,gradually decreasing width, through which air travels at a gradually increasing velocity. "llhe blade is sharpened at its lower edge and the passage between the edge and the bottom of the trough is not greater in area sie than the area of the passage between the blade and the wall 6 so that there is no reduction in the velocity of the air.

Arranged adjacent the blade 9 on th opposite side from the air chamber, is a plate 12 having a wall 13 substantially parallel to the blade and spaced therefrom, forming an elongated narrow mixing chamber 14,. the area of which issuch that the combustible mixture is moved therethrough at high velocity, substantially equal to that of the air around'the blade edge, to prevent condensation of the atomized fuel. By this construction, only a small amount of combustible mixture is present and that is contained in the narrow mixing chamber, thereby preventing any dangerous back-fires.

At its upper'end, the blade 9'is preferably provided with a lip 15, which, with the flange 16 on the plate 12, forms a long, narrow nozzle from which the lame discharges.

The plate 12' is preferably covered with ree fractory material 17 and the nozzle is directed downward slightly, so that the flame is projected against the refractory material, which is thereby heated to a high temperature and from which vthe heat is conducted to the mixing chamber and air chamber, causing the burner to vaporize the fuel more etectively.

Means are provided for igniting the combustible mixture at the nozzle and this means may comprise the ordinary spark plug or the nozzle opening may serve as the spark gap. In the latter construction the two sides of the nozzle are insulated from each other by the'block 18 of insulating material, and the terminals of the secondary of a spark coil are connected to the opposite sides of the nozzle. The primary is provided with a suitable make and break device 19 and the rimary is in parallel with the motor 21 which drives the blower 3 and the fuel pump 7. When the electric circuit is closed, air and tuel are fed to the burner :in predetermined proportions and ignition sparks play across. the nozzle opening, and ignite the mixture.

In starting the burner from an all-cold condition, a much higher air velocity is required to atomize the fuel than after the burner becomes heated, and the burner is so constructed that'the velocity of the air decreases automatically with an increase in temperature. At the instant lof starting the burner, fuel is introduced into the trough at a predetermined rate', andthe rate at which it is introduced is greater than the rate yat which it is taken up by the air at normal velocity, when the burner is cold. This causes an accumulation of fuel in the trough, which lessens the area of the air passage below the blade and consequently increases the velocity of the air at that point. The fuel gradually accumulates in the trough,

:larsneo its level approaching the edge of the blade and thereby diminishing the area of the air passage around the edge of the blade which Consequently causes an increase in the velocity of the air at that point. This accumulation continues until the velocit of the air is such that it atomizes the cold uel in sulicient quantity to produce a combustible mixture, which is ignited at the nozzle. As-

the burner becomes heated, the rate of vaporization of the fuel increases and the accumulation of thetuel in the trough is gradually diminished, gradually diminishing the air velocity until equilibrium between the rate of vaporization and the rate of fuel feed is established. When this condition is reached,the fuel is atomized at the rate at which it is introduced, producing-a combustible mixture of predetermined quality.

lt is not essential that the blade be provided with a sharp edge, it being essential only that'it extend into the trough, so that varying amounts of accumulated fuel in the trough will cause variations in the velocity of the air passing around the blade. The trough and the blade may both be made considerably wider if desired, as shown in Fig. 3, and the blade may have a rounded lower edge, which may be concentric with or nearly concentric with the bottom of the trough. When the round end blade construction is employed l prefer to vform the end of the blade of a lesser radius than the bottom of the trough, so that a' passage of venturi shape is formed, the narrowest portion of the passage occurring at the base of the trough.

I claim:

1. A liquid fuel burner, comprising a stationary air chamber having a discharge aperture and a depending portion 'forming a trough, a blower 'for forcing air into said chamber, means for introducing fuel under pressure into said trough, and a blade disposed in the chamber and spaced from the walls thereotl and extending down into said trough, whereb formed within the c amber.

2. In a liquid fuel burner, an annular air chamber, a circular plate arranged within the air chamber and spaced therefrom, an annular blade arranged between the air chamber and plate and spaced from said plate forming a mixing chamber, a narrow,

annular passage formed by the blade between the air chamber and mixing chamber and means 'for introducing fuel into said passage.

3. In a liquid fuel burner, an annular air chamber, an annular trough formed aty the bottom ot said air chamber, an annular blade extending down into said trough to adjacent the bottom thereof, whereby a narrow, reverse passage is formed, a circular plate arranged within said blade and spaced les' a reverse passage is therefrom, and forming with said bladean down into said trough to ad'acent the botannular mixing chamber, a lilling of retom thereo',-a plate arrange adjacent said ractory material on said plate, and means blade and insulated therefrom, the `edges of for directing the flame toward said refracthe plate and blade forming a nozzle, and

5 tory material. means for producing a spark across said M 4. In a Aliquid fuel burner, an annular a1r nozzle. l chamber, means for introducing air tan- In testimony whereof I have hereunto set gentially into said chamber, a trough formmy hand at San Diego, California, this 2nd ing the bottom of said chamber into which day of Aprill9l7.

10 the fuel is introduced, a blade extending ROLAND G MRX- A,`";,"j 

